A6 2.5 TDI Glow Plug Control Module - VAGCOM

Hello everyone,

I have a 2.5 TDI V6, manufactured in 1998, with an AFB engine, and I want to change the glow plug duration using VAGCOM.

In measurement block 12, data for the preheating system is displayed.
1 = Ignore the notice.
2 = Preheat time in seconds.
3 = Supply voltage from the control unit.
4 = Coolant temperature.

For VAG 1551, the idle speed is set on channel 02 (adjustment value 32768, 800 RPM).
Channel 12 controls the preheating time. Use button 3 (higher) and button 1 (lower) to adjust it.
It seems that's how one sets the time.

Okay, this is the procedure for VAG 1551, taken from the VAG repair manual.

How do I do this with VAGCOM?
I have the following buttons under the "Advanced Features" section:

LoginCode (11)
Default setting (04)
Actuator diagnostics (03).
Recoding (07)
Adaptation (10)

What login code do I need to use to log in, and how do I then set the illumination time?

I would be grateful for help.

Regards, Snowflake.

Hello.

Adaptation = adaptation.



Best regards, Cosi.

schneeflocke wrote:

What login code do I need to use to log in, and how do I then set the illumination time?

Logincode -> Articles/Expert Insights or Search.

I believe it is not possible to adjust the glow plug duration using VAGCOM.
That would probably be a job for a chip tuner, who needs to be very familiar with the software.

ulf wrote:

I believe it is impossible to adjust the glow plug duration using VAGCOM.

Then you are hereby informed.

In the case of the EDC15, adaptation channel 12 is the key, as mentioned above.
To my knowledge, there is no channel for this in the EDC16.

Thank you to Blaumann Cosi.

I knew that "Adaption" means "adjustment." However, I wasn't really clear on how to change things where and when. I always wanted to log in first. Well, sometimes you can't see the forest for the trees.

But now I have a few more questions.

Okay, so I'm in adjustment mode and I've selected channel 12. Surprisingly, only channels 2 and 12 seem to be working. All the others probably don't function. I'd like to know if this is normal.

Channel 12 displayed the following:

Bin Bits...........Time.........Volt..........Temp
(English Translation:)
Bin Bits...........Time.........Volt..........Temp
01010000........0.47.........12.08........20.7

The set value was: 32768.

I set the value to 32850, tested it, and then saved it.
The issue is that the "Time" value is now showing as 0.00.

What's wrong now? The light is only staying on for a very short time. But it wasn't a "real cold start" because the engine had been used earlier in the morning, but then it sat for a few hours in the cold of the underground garage.

No matter what value I set, the time always displays as 0.00, even when I revert to the previous value.

Can anyone explain to me what a change of plus or minus one does, and is it normal that nothing is displayed under "Time" after I save a change?

I didn't really find anything about that in the repair manual.

By the way, @Know-it-all... I really like the interesting text in your signature. *laugh*
Okay, I've now found out that EDC 15 and EDC 16 are engine control unit (ECU) designations, but what do they actually mean? What does "EDC" stand for, and how do I know if I have an EDC15 or an EDC16?
Greetings to everyone...

Snowflake.

Besswerwisser wrote:

In the case of EDC15, adaptation channel 12 is the key

.
Oh, thanks, I'll have to try that sometime.
Is it possible to adapt the ignition timing somewhere?
Our ALH Ibiza is still going strong after all this time...

schneeflocke wrote:

The following was displayed on channel 12: Bin Bits...........Time.........Volt..........Temp (English Translation:) Bin Bits...........Time.........Volt..........Temp 01010000........0.47.........12.08........20.7 The set value was: 32768. I set the value to 32850, tested it, and then saved it. The issue is that the "Time" value is now showing as 0.00. What's wrong now? The lamp is only lighting up for a very short time.

Well, if you don't know how big the change is with each step (and, more importantly, in which direction it's going!), then it's essentially just trial and error.

Apparently, higher adaptation values shorten the warm-up time, which means that lower values would extend the time.
But you took 88 steps at once -> why don't you try being a little more gentle ?

schneeflocke wrote:

No matter what value I set, the time always displays as 0.00, even when I revert to the previous value. Snowflake

Hello Ulf,

I must have written that it doesn't matter what value I set.
The "Time" field always displays "0.00" for values both above and below the original value.

And of course, when I first saved the values, I incrementally increased or decreased them by 1. But the time field stopped displaying anything after the first change.

It seems impossible to achieve anything in the time domain by changing the adaptation value.

As far as I know, the adaptation values work in such a way that a higher adaptation value results in an upward adjustment. (At least, that's how it works with adjustments to the speed, etc.).

But perhaps there's a very simple explanation for this. The coolant temperature was 20 degrees, even though the vehicle had been sitting for about 3 hours. It was last used yesterday evening at 12:30 AM. This morning at 10:00 AM, I got the same result.
The temperature displayed 17 degrees. The timer is set to 0.00. I didn't measure the outside temperature in the garage, but the actual outside temperature was -2 degrees. I estimate the temperature in the garage was around 7+ degrees.

"Of course, the glow plug duration is likely influenced by the outside temperature and the coolant temperature. But why did it show 0.47 before I stored the data? Since the ignition needs to be running when using VAGCOM, and I also had two start attempts, the temperature was 23 degrees afterward."
Despite everything, the preheating lamp originally always glowed for the same amount of time, regardless of the outside temperature (that was my subjective impression). And currently, it only glows for a very short time.

I'll probably need to check again if the vehicle hasn't been moved for 2 days, to make sure it's completely cooled down.

Just like Ulf, I'm interested in whether a post-glow period can be adapted. But perhaps this is dependent on the pre-glow duration that is set. I would certainly be happy to hear if the A6 of my year of manufacture already has a post-glow function.

Hopefully, someone among you is very familiar with the relationship between cooling temperature/outside temperature and the VAG adaptation value, as well as the effects of increasing the steps.


Regards, Snowflake.

schneeflocke wrote:

So, I'm currently in the adjustment phase and have selected channel 12. Surprisingly, only channels 2 and 12 seem to be working. All the others probably don't function. I would like to know if this is normal.

It's perfectly normal; not all channels are always activated, and there are often different login levels depending on the purpose you want to achieve.

Channel 2 is used for the idle speed in the case of EDC 15.

schneeflocke wrote:

The set value was: 32768

So, half of 65535...

schneeflocke wrote:

I set the value to 32850, tested it, and then saved it.

If you go back into the channel now, will you have 32768 again?

schneeflocke wrote:

I didn't really find anything about that in the repair manual.

The adaptation channels for engine control units are very rarely documented, let alone described in detail in the repair manuals.

schneeflocke wrote:

By the way, @Know-it-all... the text in your signature is very interesting, I like it. *laughing*

Thank you.

schneeflocke wrote:

So, I've now found out that EDC 15 and EDC 16 are engine control unit designations, but what do they actually mean, or what does EDC stand for? And how do I know if I have an EDC15 or an EDC16?

EDC = Electronic Diesel Control, and 15 and 16 essentially indicate the generation. How to know this... it's best to ask someone who is familiar with it...

ulf wrote:

Is it possible to adapt the afterglow time somewhere?

I don't know.

schneeflocke wrote:

It seems impossible to achieve anything in the time field by changing the adaptation value.

Don't rely too heavily on the measured values, as they don't always reflect the set values. Instead, in this case, measurement group 012 is displayed, and if I'm correct (please correct me if I'm wrong), it shows the currently valid preheating time from the last preheating cycle. So, if you change the value, nothing will happen – which is perfectly normal, in my opinion.

schneeflocke wrote:

Furthermore, to my knowledge, this is related to the adaptation values in such a way that a higher adaptation value causes an upward change. (At least, that's how it works with adaptations of the speed, etc.).

It's not always the case, and switching from one channel to another can be fatal...

Hello, know-it-all.

Besswerwisser wrote:

If you go back into the channel now, will you have 32768 again?

Also alle Werte die ich eingebe und speichere bleiben auch erhalten und werden beim nächsten Aufruf auch angezeigt. That works.

Besswerwisser wrote:

EDC = Electronic Diesel Control, and 15 and 16 essentially indicate the generation. How to know this... it's best to ask someone who is familiar with it...

Somewhere in the forum, I read that for EDC15, the idle speed is probably set in channel 2. So, I probably have EDC15.

Besswerwisser wrote:

Don't rely too heavily on the measured values, as they don't always reflect the set values. Instead, in this case, measurement group 012 is displayed, and if I'm correct (please correct me if I'm wrong), it shows the currently valid preheating time from the last preheating cycle. So, if you change the value, nothing will happen there - which is perfectly normal from my perspective.

That certainly reassures me.
So, I'm curious to see if I'll receive another time announcement soon.

Besswerwisser wrote:

It is not always the case, and closing one channel while another is open can be fatal...

You are right, but I extracted that information from a text where "Kanal2" (Channel 2) was mentioned in the same sentence as "Leerlaufdrehzahl" (idle speed), and "Kanal12" (Channel 12) was mentioned in the same sentence as "Glühzeit" (glow time).
Both were treated the same way. And therefore, I didn't approach the matter naively. Also, I have a copy of my engine control unit's software on a floppy disk.

(At idle speed,...)
32768 = 800 RPM
32758 = 790 rpm

Do you have any idea how to calculate the heating time based on the adjustment value, or what change in heating time a "10" step represents?
Increase by 1 = 1 second?

Regards, Snowflake.

Hi,

Changing channel 12 doesn't alter the glow time itself. Instead, it modifies the temperature that the EDC uses for its time calculations, and it only changes it in one direction, which ideally leads to shorter glow times. Experimentation isn't helpful either, because the displayed glow coil temperature often doesn't accurately reflect the actual glow process.

@Snowflake, why do you want to change something here? Maybe there's another way to do it...

Hi @bafische

bafische wrote:

Hi, Changing channel 12 doesn't alter the glow time itself. Instead, it modifies the temperature that the EDC uses for its time calculations, and only in one direction, which ideally leads to shorter glow times. Experimentation isn't helpful either, as the displayed glow coil temperature often doesn't accurately reflect the actual glow process.

Don't be angry with me, you can tell me a lot of things, but I'm not going to believe you right now. You'll have to convince me. With what literature do you want to support this statement?

Your statement doesn't align with the fact that users can input both larger and smaller values.

Given that the temperature field, as initially described, indicates the cooling water temperature, it is likely that the heating time varies depending on the cooling water temperature.
But, as far as I can tell, the coolant temperature cannot be adjusted through an input in the control unit, but rather by turning the engine on or off.
(Please don't take this paragraph too seriously. ...it's meant to be funny! <jk>)

A few years ago, VAG reduced the preheating time for my car. They didn't want me to use biodiesel. Up until that point, the starting process was excellent, regardless of the fuel used. They even told me that they had reduced the preheating time and that I should contact them if I experienced any problems.
It's quite rude to change things that are working and simply steal customers' time by making them visit the workshop again. But let's leave that aside. That's not a productive approach.

I probably need to replace my glow plugs soon. I'll get around to that sometime. I prefer ones that glow for a long time, but that's a different topic. Here, I just want to clarify the details regarding the glow time and the necessary adjustments to the engine control unit.

bafische wrote:

The display of the filament and actual glowing usually have very little in common.

That may be correct in the sense that the indicator on the dashboard only shows the preheating time and not the total heating duration, which includes the afterglow.

Maybe you should read this article about it sometime...

http://forums.tdiclub.com/showthread.php?t=123304

Thanks again to @Besswerwisser.

Okay, so the heating time is based on the previous heating cycle.

The preheating time for a KWTemp value greater than 17° is approximately 0.00.

At a KWTemp of 6°, the value is 3.76. So, everything is working.
I don't know exactly what difference an increase of 10 makes, but it's something like that.
Will I be able to figure this out if I take another measurement of the KW temperature tomorrow under similar conditions?

And that's what it looked like...

http://people.freenet.de/freitag_gruppe/Gluehzeit.pdf



Does anyone have a list or an idea of what the optimal preheating time is for different temperatures? Can the glow plugs fail or become fouled if they are preheated for too long?
Also, I would also like to know if my engine control unit initiates a post-glow period for the glow plugs.


UPS @Besswerwisser, it seems our writing overlapped. *laugh* Are you also a "night owl"? *grin*

Yes, great, thank you for the article... maybe I should have looked around more there. Of course, the article is unbeatable.
Now I can sleep soundly. Good night .

schneeflocke wrote:

Don't be angry with me, people can tell you a lot of things, but I don't believe you right now. You have to convince me. With which literature do you want to support this statement?

Hi Snowflake,

[offensive mode on]
It should be clear from my previous ratings that I am not constantly spreading nonsense in this forum about diesel engines. I neither want to nor will I try to convince anyone here; everyone should have their own opinion. Furthermore, nothing can be proven here or on the internet in general; that is the responsibility of others. This forum should rather aim to share and preserve a certain amount of knowledge, and at the end of each thread, there should be a reasonably reliable statement, rather than a wild guess, so that the confusion is minimized, not increased.
[insult mode on]

With V6 engines equipped with the VP44 injection pump, it is 98% impossible to achieve what is described in the link provided by "Know-it-all." However, I am not familiar with every variant, and I could also be mistaken.
The 4-cylinder engines differ from the 6-cylinder engines, as do almost all other SG variants, so a case-by-case analysis is essential. However, the effect on temperature is the same for all. You will also notice this if you experiment with the adjustments often enough using VAG-COM. There is no linear behavior, as with other adjustment functions.
But only practice makes perfect.

If you provide me with the SG identification, I may be able to give you a more precise answer.

The following parameters are relevant for the MWB12: water temperature, preheating time, and battery voltage.

Quote:

bafische wrote: The display of the filament and actual glowing usually have very little in common. That may be correct in the sense that the display on the dashboard only indicates the preheating time and not the total heating duration, which includes the afterglow.

That's not what I meant; it was specifically related to the preheating time. A good example: sometimes it starts to glow even before the driver turns on the ignition (but don't worry, it won't happen with yours).

Quote:

Furthermore, I would also like to know if my engine control unit initiates a post-glow period for the glow plugs.

You can find information about afterglow and its duration in document MWB 12/1. The repair manuals describe what "afterglow" means. I believe it's from December 11th. If you can't find it, I can search for it again.

Quote:

Does anyone perhaps have a list or an idea of what preheating time is appropriate for which temperature? Can the glow plugs fail or become clogged due to preheating for too long?

The preheating and temperature settings aren't quite as straightforward because the optimal preheating time depends on dozens of factors (e.g., type of glow plug, vehicle electrical system, injector spray pattern, compression, etc.).
To gradually get acquainted with the topic, take a look here.

http://www.beru.com/download/produkte/TI04_d.pdf

Here you'll find a diagram showing a scatter plot of possible ignition times depending on temperature/hardware variant. Additionally, there's a concise and largely accurate summary of the potential damage to glow plugs.

I would recommend these pages to anyone who wants to learn about the basics of incandescent lamp control.

Snowflake, it would be great if you could tell us more about your attempts to gain a clearer perspective on things here.

Modified!!!

bafische wrote:

[offensive mode on]

snowflake <= I apologize, but my previous comment was not meant to be taken that way!

bafische wrote:

[insult mode on]

Oops, I had another "Schwein" moment.

bafische wrote:

With V6 engines equipped with the VP44 injection pump, it is 98% impossible to achieve what is described in the link provided by "Know-it-all." However, I am not familiar with every variant, and I could also be mistaken.

Okay, the link from @Besswerwisser is fine.
However, I can only modify values above 32768 without having to enter a login.
I don't really understand that.
In my previous messages, I stated that I could adapt in both directions. I didn't realize that while I can enter a value below 32768 and click the "save" button, I didn't notice that the value resets back to the original value of 32768.

At 5.4°C, the exposure time is 6.11 seconds at 32768... I will upload the images later.

Okay, so I thought I had to log in to enter values below a certain threshold. But that's not the case. While logging in works with the code, everything becomes incredibly slow. I can barely access the settings anymore, I can't switch channels properly, and I'm getting the usual error messages...
Too many communication errors, etc., etc. As a result, nothing works anymore.
I'm disappointed!

bafische wrote:

If you provide me with the SG identification, I may be able to give you a more precise answer.

Sorry, I don't even know what an SG identification is, let alone an MWB12... I'm just a newbie. *laugh*

bafische wrote:

That's not what I meant; it was specifically related to the preheating time. A good example: sometimes it starts to glow even before the driver turns on the ignition (but don't worry, it won't happen with yours).

"Yes, I know, it was like that with some older Golfs, probably GTDs, but they stopped doing it during the TDI era. But it was definitely "awesome." I've often thought that it would be great if my car had that feature in the winter."

bafische wrote:

You can find information about whether your candles afterglow and for how long in document MWB 12/1. The repair manuals describe what "afterglow" means. I mean December 11th. If you can't find it, I can search again.

Thank you for the offer and the link. I had already seen the link, as I am currently looking for candles, but it is still a really good and recommendable link.


Regards, Snowflake.

schneeflocke wrote:

However, I can only modify values above 32768 without having to enter a login. I don't really understand that. In my previous messages, I claimed that I could adapt in both directions. I didn't realize that while I can enter a value below 32768 and press the "save" button, I didn't notice that the value resets back to the original value of 32768.

As mentioned above, you can only adapt in one direction, namely to shorter exposure times, by using temperature as an intermediary.
In the measurement block 12 of VAG-COM (by the way, when I say "MWB12/1", I mean measurement block or display block No. 12 with the 1st value, which is the leftmost value on the display. So, 12/1 is the glow plug status, 12/2 is the pre-glow time, 12/3 is the battery voltage, and 12/4 is the water temperature), you will find all the information.
You have already discovered that you do not need a login to adapt channel 12 on your V6, so you can stop all attempts to log in.

Now, let's move on to determining the optimal heating time.

You have measured the following:
Your ignition duration is 6.11 seconds (12/2) at a water temperature of 5.4°C (12/4) without adaptation, which results in a value of 32768.
Furthermore, your ignition time is 0.47 seconds (12/2) at a water temperature of 17°C (12/4), even without adaptation, so it's also 32768 - both values I obtained from your posts.

For simplicity, let's assume that the heating time is linearly proportional to the water temperature. This allows us to calculate (or rather, estimate) the heating time for any given water temperature. For example, the heating time at 11.2°C should be approximately 3 seconds, and above 20°C, it would be 0 seconds.

Now we're adapting channel 12; it's only going to higher values, as you've already figured out.
For example, if you're at 5.4°C and then adjust to a higher setting, the computer thinks: "It's not actually 5.4°C, but 5.4°C plus a temperature 'X' that corresponds to the adjustment step." Therefore, the computer searches for the appropriate heating time for a higher temperature, and since higher temperatures can also mean shorter heating times, the heating time may only decrease during adaptation.
If you measure the glow time at all possible temperatures and try out different adaptation settings, you can calculate your own glow time characteristic curve and the adaptation step size. But remember, after the adaptation, turn off the ignition, wait 10 seconds, and then turn the ignition back on – only then will MWB12/2 display the changed value after the adaptation.

For the afterglow:
Yes, it is "11".
Okay, so if the leftmost value in the measurement block 12 (the seemingly random 8 characters, consisting only of zeros and ones - i.e., a 16-bit integer, binary value) converts to 11 in decimal, your LEDs will glow until that value becomes 0 (with the engine running, of course). Please note the CPU-specific arrangement of the high byte and low byte, so that:
11 in the decimal system - 0000 1011 in the binary system.
11 in the decimal system corresponds to 1011 0000 in the binary system, which is used in our control units.

So, if MWB12/1 = 10110000 immediately after a cold start with the engine running, and it gradually decreases until MWB12/1 = 00000000, this is, of course, also temperature-dependent.

@ Snowflake, could you give us some feedback on whether my theoretical construct also holds true in practice?